MINLP optimization of structures

The paper discusses the mixed-integer non-linear programming (MINLP) approach to the optimization of structures. The MINLP is an optimization technique which is able to solve non-linear and discrete optimization problems. It calculates continuous variables (loads, dimensions, stresses, deflections, costs) and discrete variables (topology, standard sections, material grades). The MINLP optimization model of a structure should be developed. In the model, an objective function is subjected to structural analysis and dimensioning constraints in order to satisfied ultimate and serviceability limit states according to Eurocodes. Appropriate MINLP algorithms and strategies are used to solve the defined MINLP problem. Two numerical examples are presented at the end of the paper

Distributed Multi-writer Multi-reader Atomic Register with Optimistically Fast Read and Write

A distributed multi-writer multi-reader (MWMR) atomic register is an important primitive that enables a wide range of distributed algorithms. Hence, improving its performance can have large-scale consequences. Since the seminal work of ABD emulation in the message-passing networks [JACM '95], many researchers study fast implementations of atomic registers under various conditions. "Fast" means that a read or a write can be completed with 1 round-trip time (RTT), by contacting a simple majority. In this work, we explore an atomic register with optimal resilience and "optimistically fast" read and write operations. That is, both operations can be fast if there is no concurrent write. This paper has three contributions: (i) We present Gus, the emulation of an MWMR atomic register with optimal resilience and optimistically fast reads and writes when there are up to 5 nodes; (ii) We show that when there are > 5 nodes, it is impossible to emulate an MWMR atomic register with both properties; and (iii) We implement Gus in the framework of EPaxos and Gryff, and show that Gus provides lower tail latency than state-of-the-art systems such as EPaxos, Gryff, Giza, and Tempo under various workloads in the context of geo-replicated object storage systems

Effective utilization of optimization algorithms on machining operations

155-168Optimization is ruling the entire field of machining and material processing technology from the time at which the revolution took place in machining processes. Various types of machining algorithms have been developed so far for optimizing the independent control factors in order to get the improved results of desirable output responses. Each algorithm has its own special features which made them useful in deriving the optimized solutions under different conditions. Suitable algorithm is chosen for the required case depending upon the nature of the problem, the requirement of the order of precision and the availability of optimization tools. In this review article, the general flow of few important algorithms has been explained in a simpler manner to be understood by the recent researchers. Also, required numbers of case studies for each algorithm have been provided extensively. This consolidated work will surely be helpful for the new researchers those who have entered into the domain of optimization

Improving Broiler Performance and Digestibility Through Feed Enzymes and Production Rate Aids Utilized in Pelleting.

Enzymes are commonly added to poultry diets to improve performance parameters that may in turn decrease costs to the producer. Pellet mill production rate aids are also utilized to reduce feed manufacture costs and may have additional benefits when fed to poultry that are associated with the increase in production rate. Past research has shown that Azomite (AZM) can increase pellet mill production rate in diets that include inorganic phosphate sources (IPS) of dicalcium phosphate (DCP) or tricalcium phosphate (TCP). In the first experiment the authors hypothesized that if production rate were held constant then pellet mill energy consumption would decrease for diets that contained AZM due in part to a lubricating and/or pellet die scouring effect. This could decrease dietary amino acid exposure to frictional heat and pressure within the pellet die, maintaining amino acid conformation, and amino acid digestibility. The objective was to determine the effect of AZM (0.25%) in diets with DCP and TCP on pellet mill energy consumption, subsequent live bird performance, and apparent ileal amino acid digestibility (AIAAD) when fed to broiler chicks for 21 days. Feed was manufactured in a 2 (IPS) x 2 (AZM inclusion) factorial across 4 days in a Latin square design. Post manufacture, three hundred twenty-day-old Hubbard × Ross 708 males (0.038kg ± 0.0014 SD) were allocated by weight to 8 replicates per treatment, 10 chicks per raised wire cage, in a randomized complete block design. Dietary treatments were arranged in a 2 x 2 factorial: DCP with or without AZM and TCP with or without AZM. On d21 ileal contents were collected for amino acid and titanium dioxide analysis. Statistical analysis (Glimmix, SAS 9.4) was performed on the factorial arrangement of treatments and multiple comparisons were made of all treatments with post-hoc test by Tukey’s. Pellet mill motor load decreased by 5% in diets containing TCP compared to DCP (P Mixer added phytases must retain efficacy post conditioning and pelleting. Heat from saturated steam and friction upon pellet die extrusion may deactivate phytases. In addition, increasing phytase concentrations in diets may increase nutrient release from phytate. In this second experiment the objective was to assess two commercially available phytases that were concentrated at 500, 1,000, or 2,000 FTU/kg in mixed mash post steam conditioning at 82°C for 30 sec and extrusion through a 4.8 x 38mm pellet die on 0 to 44d Ross 708 male broiler performance, mineral digestibility, and tibia ash responses. The phytase sources were both derived from E. coli and expressed in Trichoderma Reesei, (QB) and expressed in Pichia pastoris, (OP). A 3 (Phytase level) × 2 (Phytase source) factorial arrangement of treatments within a randomized complete block design was utilized. A positive control and negative control diet based on available phosphorus (P) and total calcium (Ca) were also manufactured and analyzed within a multiple comparison. Crumbled and pelleted diets were fed to 8 replicate pens of 30 chicks in three phases. Live performance, d20 and d44 tibia ash, d44 hot boneless, skinless breast weight and mineral digestibility were measured. Day 44 live weight gain (LWG) and both d20 and d44 tibia measures increased for all phytase concentrations relative to the negative control (P\u3c0.05)

An Empirical Investigation of the Willingness of US Intelligence Community Analysts to Contribute Knowledge to a Knowledge Management System (KMS) in a Highly Classified and Sensitive Environment

Since September 11, 2001, the United States Government (USG) has possessed unparalleled capability in terms of dedicated intelligence and information collection assets supporting the analysts of the Intelligence Community (IC). The USG IC has sponsored, developed, and borne witness to extraordinary advances in technology, techniques, and procedures focused on knowledge harvesting, knowledge sharing, and collaboration. Knowledge, within successful (effective & productive) organizations, exists as a commodity; a commodity that can be created, captured, imparted, shared, and leveraged. The research problem that this study addressed is the challenge of maintaining strong organizational effectiveness and productivity through the use of an information technology-based knowledge management system (KMS). The main goal of this study was to empirically assess a model testing the impact of the factors of rewards, power, centrality, trust, collaborative environment, resistance to share, ease-of-using KMS, organizational structure, and top management support to inducement, willingness to share, as well as opportunity to contribute knowledge to a KMS on knowledge-sharing in a highly classified and sensitive environment of the USG IC. This study capitalized on prior literature to measure each of the 15 model constructs. This study was conducted with a select group of USG Departments and Agencies whose primary interest is Intelligence Operations. This study solicited responses from more than 1,000 current, as well as former, Intelligence Analysts of the USG IC, using an unclassified anonymous survey instrument. A total of 525 (52.5%) valid responses were analyzed using a partial least squares (PLS) structural equation modeling (SEM) statistical technique to perform model testing. Pre-analysis data screening was conducted to ensure the accuracy of the data collected, as well as to correct irregularities or errors within the gathered data. The 14 propositions outlined in this research study were tested using the PLS-SEM analysis along with reliability and validity checks. The results of this study provide insights into the key factors that shed light onto the willingness of US intelligence community analysts to contribute knowledge to a KMS in a highly classified and sensitive environment. Specifically, the significance of a knowledge worker’s willingness to contribute his/her knowledge to a KMS along with the opportunity to contribute knowledge, while inducement was not a significant factor when it comes to knowledge sharing using KMS in highly classified environments

Development of a hybrid metaheuristic for the efficient solution of strategic supply chain management problems: application to the energy sector

Supply chain management (SCM) addresses the strategic, tactical, and operational decision making that optimizes the supply chain performance. The strategic level defines the supply chain configuration: the selection of suppliers, transportation routes, manufacturing facilities, production levels, technologies. The tactical level plans and schedules the supply chain to meet actual demand. The operational level executes plans. Tactical and operational level decision-making functions are distributed across the supply chain. To increase or optimize performance, supply-chain functions must be perfectly coordinated. But the cycles of the enterprise and the market make this difficult: raw material does not arrive on time, production facilities fail, workers are ill, customers change or cancel orders, therefore, causing deviations from the plan. In some cases, these situations may be dealt with locally. In other cases, the problem cannot be ”locally contained” and modifications across many functions are required. Consequently, the supply chain management system must coordinate the revision of plans or schedules. The ability to better understand an algorithm is important to focus on the following variables: tactical and operational levels of the supply chain so that the timely dissemination of information, accurate coordination of decisions, and management of actions among people and systems is achieved ultimately determines the efficient, coordinated achievement of enterprise goal

Literature review on the potential of urban waste for the fertilization of urban agriculture : A closer look at the metropolitan area of Barcelona

Unidad de excelencia María de Maeztu CEX2019-000940-MUrban agriculture (UA) activities are increasing in popularity and importance due to greater food demands and reductions in agricultural land, also advocating for greater local food supply and security as well as the social and community cohesion perspective. This activity also has the potential to enhance the circularity of urban flows, repurposing nutrients from waste sources, increasing their self-sufficiency, reducing nutrient loss into the environment, and avoiding environmental cost of nutrient extraction and synthetization. The present work is aimed at defining recovery technologies outlined in the literature to obtain relevant nutrients such as N and P from waste sources in urban areas. Through literature research tools, the waste sources were defined, differentiating two main groups: (1) food, organic, biowaste and (2) wastewater. Up to 7 recovery strategies were identified for food, organic, and biowaste sources, while 11 strategies were defined for wastewater, mainly focusing on the recovery of N and P, which are applicable in UA in different forms. The potential of the recovered nutrients to cover existing and prospective UA sites was further assessed for the metropolitan area of Barcelona. Nutrient recovery from current composting and anaerobic digestion of urban sourced organic matter obtained each year in the area as well as the composting of wastewater sludge, struvite precipitation and ion exchange in wastewater effluent generated yearly in existing WWTPs were assessed. The results show that the requirements for the current and prospective UA in the area can be met 2.7 to 380.2 times for P and 1.7 to 117.5 times for N depending on the recovery strategy. While the present results are promising, current perceptions, legislation and the implementation and production costs compared to existing markets do not facilitate the application of nutrient recovery strategies, although a change is expected in the near future

Literature review on the potential of urban waste for the fertilization of urban agriculture: A closer look at the metropolitan area of Barcelona

Urban agriculture (UA) activities are increasing in popularity and importance due to greater food demands and reductions in agricultural land, also advocating for greater local food supply and security as well as the social and community cohesion perspective. This activity also has the potential to enhance the circularity of urban flows, repurposing nutrients from waste sources, increasing their self-sufficiency, reducing nutrient loss into the environment, and avoiding environmental cost of nutrient extraction and synthetization.The present work is aimed at defining recovery technologies outlined in the literature to obtain relevant nutrients such as N and P from waste sources in urban areas. Through literature research tools, the waste sources were defined, differentiating two main groups: (1) food, organic, biowaste and (2) wastewater. Up to 7 recovery strategies were identified for food, organic, and biowaste sources, while 11 strategies were defined for wastewater, mainly focusing on the recovery of N and P, which are applicable in UA in different forms.The potential of the recovered nutrients to cover existing and prospective UA sites was further assessed for the metropolitan area of Barcelona. Nutrient recovery from current composting and anaerobic digestion of urban sourced organic matter obtained each year in the area as well as the composting of wastewater sludge, struvite precipitation and ion exchange in wastewater effluent generated yearly in existing WWTPs were assessed. The results show that the requirements for the current and prospective UA in the area can be met 2.7 to 380.2 times for P and 1.7 to 117.5 times for N depending on the recovery strategy. While the present results are promising, current perceptions, legislation and the implementation and production costs compared to existing markets do not facilitate the application of nutrient recovery strategies, although a change is expected in the near future